EP3435529B1 - Circuit for distortion cancellation in a dc circuit - Google Patents

Description

Field of invention

The present invention relates to the technical field of direct current networks. In particular, the present invention relates to an interference suppression device for a direct current circuit, a vehicle component, a high-voltage intermediate circuit and a vehicle.

Background of the invention

A circuit is used to supply various components with electrical energy. A single component can be operated on a circuit; However, as is often the case in an electric or hybrid vehicle, a large number of components can also be operated. However, components that are operated on a direct current circuit are susceptible to interference, in particular to alternating voltages that arise on the direct current circuit for various reasons or that are coupled onto the direct current circuit from outside and spread across the direct current circuit.

The susceptibility of a component to interference can be caused by the fact that filter components, which are actually intended to suppress interference generated by the component, are excited when interference occurs on the direct current circuit, in particular when an alternating voltage with a certain frequency occurs, that they lead to destruction of the component or individual components of the component.

The publication DD 208 019 concerns the reduction of the current load of additional chokes, which are present in a direct current system to limit the current in the event of an accident and through which the full load current also flows, for a voltage inverter for feeding three-phase machines.

The publication DE 21 60 925 A1 describes a method and filter for eliminating the hum component of a direct current.

The publication US 2005/141248 A1 relates to a power electronics system for conditioning power from a fuel cell with a boost converter, for increasing a voltage of a DC output voltage of the fuel cell and for removing a ripple through mutual inductors, with a high-frequency converter and with an AC-AC converter.

Opposite the US 2005/141248 A1 The task is therefore to obtain an alternative to the passive and transformerically and conductively coupled resonant interference suppression circuit disclosed there.

Summary of the invention

Accordingly, an interference suppression device for a direct current circuit, a vehicle component, a high-voltage intermediate circuit and a vehicle is specified.

The subject matter of the invention is specified by the features of independent claim 1.

Embodiments and further aspects of the invention are set out in the dependent claims and the following description.

According to one aspect of the invention, an interference suppression device for a direct current circuit is provided. The direct current circuit has at least two conductors. The interference suppression device has a first connection which serves to connect the interference suppression device to a first conductor of the direct current circuit and a second connection which serves to connect the interference suppression device to a second conductor of the direct current circuit. The interference suppression device also has a sensor. The sensor can be coupled to the direct current circuit essentially without contact. In one example, the property "non-contact" may refer to a galvanic coupling, since mechanical contact via a winding core of a transformer is certainly possible. In another example, a substantially complete air coupling with the direct current circuit may be able to be established, so that essentially - apart from connections via a common connection - there is no electrical coupling and no mechanical coupling between the sensor and the direct current circuit. In particular, such a connection does not exist for the transmission of a measured variable, such as the alternating current flowing in the direct current circuit. Or in other words, an alternating current flowing in the direct current circuit may be transmitted by the coupling essentially without contact.

The sensor is also set up to detect when a predeterminable limit value of a superimposed alternating voltage in the first conductor of the direct current circuit is exceeded and to substantially reduce the alternating voltage in the first conductor of the direct current circuit to the predeterminable limit value by impressing a current into the first connection and/or below the limit value. The current is recorded inductively but is impressed conductively into the direct current circuit via diodes.

According to a further aspect of the present invention, a component, in particular a vehicle component, is specified. The component can be, for example, a drive converter, an on-board power converter, a charger, an air conditioning compressor or a converter. The component has a DC circuit with a first conductor, a second conductor and an intermediate circuit filter. In addition, the interference suppression device according to the invention is present in or on the component, wherein the first connection of the interference suppression device is connected to the first conductor, the second connection of the interference suppression device is connected to the second conductor and the sensor is coupled to the intermediate circuit filter in a substantially contactless manner. Furthermore, the direct current circuit is set up for connection to a high-voltage intermediate circuit.

According to another aspect of the invention, a high-voltage intermediate circuit is specified for a vehicle. This high-voltage intermediate circuit has a supply battery, a first component which is operated at a working frequency and at least one second component. In addition, the high-voltage intermediate circuit has at least one interference suppression device according to the invention. The supply battery, the first component and the second component are each connected to a first conductor and a second conductor of the high-voltage intermediate circuit.

The first conductor of the at least one second component is connected to the first connection of the interference suppression device and the second conductor of the at least one second component is connected to the second connection of the interference suppression device. In addition, the sensor of the interference suppression device is coupled without contact to the part of the first conductor and/or the second conductor belonging to the at least second component.

The interference suppression device can also be referred to as a resonant power regeneration circuit. In this text, the terms “capacitor” and “capacitance” as well as “coil” or “choke” and “inductance” may be used interchangeably.

If components are ordered from a supplier by an OEM (Original Equipment Manufacturer), the OEM specifies a maximum permissible amplitude that must not be exceeded within a specified frequency range. If this amplitude were exceeded, the component could be damaged or destroyed. In order to prevent interference from the component to other components that are connected to the same circuit, the component itself may have an intermediate circuit filter, the filter containing at least one intermediate circuit capacitor and at least one intermediate circuit coil or an intermediate circuit choke. This intermediate circuit filter may be designed as a low-pass filter. This low-pass filter may have a resonance frequency that is well below the clock frequency at which the respective component works, e.g. a drive inverter, an on-board power converter, a charger or air conditioning compressor inverter. By designing the working frequency of the component in such a way that this frequency is far above the resonance frequency of the low pass and as far as possible outside the pass band of the low pass, it can be ensured that interference, in particular alternating current interference (AC interference, alternating current interference) or voltage -Ripples that are generated by the component are dampened and, if possible, do not spread or only spread to a small extent to the direct current circuit and/or the intermediate circuit to which the component is connected.

Despite these precautionary measures, however, it can happen that interference occurs on the intermediate circuit in the form of alternating voltages (AC) or voltage ripples that have a frequency that is lower than the operating frequency of a component, but in the resonant frequency range of the intermediate circuit filter belonging to the component lies. Such a disturbance is then able to generate resonant oscillations in the filter, which can lead to an increase in voltage, which in turn can damage components of the component, since the increase in voltage is directed in the direction of the internal components of the component. Or in other words, the structure of a filter component, for example a second or higher order filter, can attenuate disturbances in the range of the component's operating frequency that propagate from the component towards the intermediate circuit. However, low-frequency oscillations (AC), which propagate in the intermediate circuit in the direction of the internal components of the component and which have a frequency in the range of the resonance frequency, can increase in such a way that they can lead to damage to the components of the components. Or in still other words, dampens it Intermediate circuit filter alternating interference (AC) in the range of the working frequency of the component well in the direction of the intermediate circuit, but amplifies alternating interference (AC), which has a frequency in the range of the resonance frequency, and propagates from the intermediate circuit in the direction of the component and in particular in Direction of the interior of the component.

The interference that propagates from the intermediate circuit in the direction of the component could be suppressed by damping with the help of additional filters and/or a filter designed for a correspondingly large frequency range. However, the filters would have to be designed to be correspondingly large, which would increase the weight and cost of the filter. In addition, steaming involves energy losses and could lead to high losses. With the help of the interference suppression device according to the invention, however, the current caused by the voltage increase can be used by feeding or impressing it back into the intermediate circuit or direct current circuit and the energy contained in it is essentially preserved, i.e. not destroyed.

The sensor for contactless coupling with the first conductor of the direct current circuit has a coil in order to form a transformer with a predeterminable coupling factor with the direct current circuit.

By means of the coil, a current can be tapped in the interference suppression device essentially without loss, which can be fed back into the direct current circuit or the intermediate circuit in order to counteract the interference. The interference suppression coil can be wound on a common ferrite core with the intermediate circuit filter coil. The coils are essentially galvanically isolated, particularly in relation to voltage transmission. The coupling factor k indicates how closely the coupling corresponds to an ideal coupling. With an ideal coupling, the coupling factor k=1, ie the total magnetic flux through the primary coil corresponds to the flux through the secondary coil. In a real coupling, a leakage flux can occur so that k<1, for example k=0.9. The turns ratio of the interference suppression coil to the intermediate circuit filter coil can be, for example, 1:10 or 1:20, regardless of the coupling factor k.

A first connection of the coil, in particular a first connection of the interference suppression coil, is connected to the first connection and a second connection of the coil is connected to the first connection via at least one capacitor, in particular via the interference suppression capacitor, and via at least one diode. By connecting the interference suppression coil in this way, a current tapped by means of the interference suppression coil can be impressed and/or fed back into the first connection and thus into the intermediate circuit.

A connection of the at least one capacitor, in particular the interference suppression capacitor, is connected to the second connection via a further diode.

The second connection can be a reference potential, for example ground.

According to a further aspect of the present invention, the first connection and the second connection are designed for connecting to a vehicle component.

If the interference suppression device is intended for subsequent installation in an intermediate circuit, the first and second connections can, for example, be made using a plug-in connection that is common for intermediate circuits, which greatly simplifies the retrofitting of an intermediate circuit with the interference suppression device. In addition to connecting the interference suppression device to the first conductor and to the second conductor, it may be necessary to bring the interference suppression coil close to the intermediate circuit coil in order to be able to provide a good coupling factor.

The sensor of the interference suppression device is designed to be coupled to a filter coil and/or line inductance of a direct current circuit.

In order to increase the effectiveness of a coupling, the supply line can be routed through at least one toroidal core. If the supply line is through one or a plurality of toroidal cores which are wound with the interference suppression coil, this line inductance acts as a DC link filter coil, since the line inductance is increased by means of one and/or the plurality of toroidal cores.

Depending on the characteristics of the line inductances, not only the filter coil or intermediate circuit filter coil but also line inductances that contribute to the coupling and/or to the interference caused by the impressed alternating voltage (AC) must be taken into account. These may need to be taken into account when dimensioning the interference suppression coil or determining the number of turns.

According to a further aspect of the present invention, the interference suppression device is designed to be connected to a direct current circuit or direct current intermediate circuit which has a direct voltage of 400 V or 900 V.

According to a further aspect of the present invention, the interference suppression device has a housing, wherein the housing is designed to be attached to a vehicle. The housing can be a robust housing that meets the standards for installing additional components in a vehicle, in particular an electric vehicle.

According to one aspect of the present invention, an interference suppression device is specified which is connected to a direct current network or intermediate circuit. The intermediate circuit may have a large number of inductances and capacitances, which are essentially formed by the intermediate circuit filters of the components connected to the DC network. When excited with an alternating voltage with a defined frequency above a defined amplitude, the resonant circuit amplitude is limited by the LC filter and the energy of the interference suppression device, the resonant circuit or the LC filter may be fed back into the direct current network as direct current. A different maximum permissible amplitude can be specified for each frequency. In particular, if the intermediate circuit filters of different components have different resonance frequencies and/or different maximum permissible amplitudes or voltage amplitudes, a different maximum permissible amplitude may be specified for each frequency. In order to carry out interference suppression individually for each component, each component connected separately to the HV bus (high-voltage bus, high-voltage bus, intermediate circuit) is individually suppressed. To define a component, for example, the housing can be set as the component boundary. In this way it is also possible if If several components are located in the same housing, the common connection to the HV bus can be used to suppress interference for all components.

Essentially, the invention is based on the knowledge that a resonant circuit, which is intended to prevent the propagation of a disturbance from a component in the direction of other components, passes on a disturbance to the component in an amplified manner when a disturbance in the opposite direction from other components to the Oscillating circuit hits. Or in other words, this may mean that an oscillating circuit behaves asymmetrically in different directions at different frequencies.

Short description of the characters

• Fig. 1 Zeigt einen Hochspannungs-Zwischenkreis mit angeschlossenen Komponenten gemäß einem exemplarischen Ausführungsbeispiel der vorliegenden Erfindung.
• Fig. 2 zeigt ein Teilersatzschaltbild der Filterbauteile der Komponenten des Zwischenkreises aus Fig. 1 gemäß einem exemplarischen Ausführungsbeispiel der vorliegenden Erfindung.
• Fig. 3 zeigt ein Ersatzschaltbild für eine Entstörvorrichtung, welche an einen Zwischenkreis und ein Zwischenkreisfilter einer Komponente angeschlossen ist.
• Fig. 4 zeigt eine Selektion von Frequenzdiagrammen für ein Störsignal mit einer geringen Störamplitude gemäß einem exemplarischen Ausführungsbeispiel der vorliegenden Erfindung.
• Fig. 5a zeigt eine Selektion von Frequenzdiagrammen für ein Störsignal mit einer großen Störamplitude bei 900V Zwischenkreisspannung gemäß einem exemplarischen Ausführungsbeispiel der vorliegenden Erfindung.
• Fig. 5b zeigt eine Selektion von Frequenzdiagrammen für ein Störsignal mit einer großen Störamplitude bei 450V Zwischenkreisspannung gemäß einem exemplarischen Ausführungsbeispiel der vorliegenden Erfindung.
• Fig. 6 zeigt ein Ersatzschaltbild für eine weitere Ausgestaltung einer Entstörvorrichtung mit vervielfachten Elementen gemäß einem exemplarischen Ausführungsbeispiel der vorliegenden Erfindung.

Further exemplary embodiments of the present invention are described below with reference to the figures.

• Fig. 1 Shows a high-voltage intermediate circuit with connected components according to an exemplary embodiment of the present invention.
• Fig. 2 shows a partial equivalent circuit diagram of the filter components of the intermediate circuit components Fig. 1 according to an exemplary embodiment of the present invention.
• Fig. 3 shows an equivalent circuit diagram for an interference suppression device, which is connected to an intermediate circuit and an intermediate circuit filter of a component.
• Fig. 4 shows a selection of frequency diagrams for an interference signal with a low interference amplitude according to an exemplary embodiment of the present invention.
• Fig. 5a shows a selection of frequency diagrams for an interference signal with a large interference amplitude at 900V intermediate circuit voltage according to an exemplary embodiment of the present invention.
• Fig. 5b shows a selection of frequency diagrams for an interference signal with a large interference amplitude at 450V intermediate circuit voltage according to an exemplary embodiment of the present invention.
• Fig. 6 shows an equivalent circuit diagram for a further embodiment of an interference suppression device with multiple elements according to an exemplary embodiment of the present invention.

Detailed description of exemplary embodiments

The representations in the figures are schematic and not to scale. In the following description of the Fig. 1 to Fig. 6 the same reference numbers are used for the same or corresponding elements.

Fig. 1 Shows an intermediate circuit 100 or HV bus 100 with connected components 102a, 102b, 102c, 102d according to an exemplary embodiment of the present invention. The high-voltage intermediate circuit 100 of an electric and hybrid vehicle has a first line 103 and a second line 104. These are supplied by the battery 101, for example a Li-ion battery, with a direct current (DC) of 400 V, 450 V or 900 V. The voltages can be chosen arbitrarily. Without limiting generality, voltages 300 V, 350 V, 400 V, 450 V, 500 V, 550 V, 600 V, 650 V, 700 V, 750 V, 800 V, 850 V and 900 V can also be selected. In particular, any voltages from the range of 300 V to 900 V are also possible. The voltages can also lie within a tolerance range of the specified values. Several components 102a, 102b, 102c, 102d are connected to the high-voltage intermediate circuit 100. The components are the high-voltage battery 101, the drive converter 102a, which is connected to the engine, the on-board power converter 102b, the charger 102c or the DC-DC converter 102c, the AC / DC converter 102d, the air conditioning compressor -Inverter and any number of other components. With the exception of the battery 101, these components 102a, 102b, 102c, 102d contain electronic converters which periodically load the intermediate circuit 100 with sometimes high currents at a clock frequency in the range of 5 to 500 kHz. These converters have switches that are switched according to the respective clock frequency of the associated component.

The Fig. 2 shows a partial equivalent circuit diagram of the filter components of the components 101, 102a, 102b, 102c, 102d of the intermediate circuit 100 Fig. 1 according to an exemplary Embodiment of the present invention. Fig. 2 shows in particular an equivalent circuit diagram, which results for an interference alternating voltage 206a, which can arise in the inverter 102a due to switching processes. In each of the components 102a, 102b, 102c, 102d, which has a changeover switch that is operated at a certain frequency, the switching can cause loads or disturbances in the form of an alternating voltage (AC) 206a or a voltage ripple 206a to form. The interference voltage 206a, in particular the interference alternating voltage 206a, can be understood as a voltage source 206a, B1a.

In Fig. 2 The emergence of a fault is shown in the case of the inverter 102a for the energy supply of a 100 kW drive motor for an electric vehicle, which, as a generator, generates a drive current of 400 A for the drive motor of the vehicle. The interference current 206a is absorbed by the intermediate circuit capacitor 205a, which creates an interference voltage on the intermediate circuit 100, 103, 104 or on the HV-DC bus 100, 103, 104, which can in principle excite all filter circuits connected to it to oscillate. The disturbances 206a caused by this can spread from the causing component 102a in the direction of the intermediate circuit 100 and reach the other components 102b, 102c, 102d via the intermediate circuit 100. The intermediate circuit 100 or DC bus 100 is operated as a direct current circuit (DC). The battery 101 generates a direct voltage VB of, for example, 400V, 450V or 900V, which is superimposed on the interference alternating voltage V _AC . So that this load caused by the interference alternating voltage 206a does not impair the function of other components 102b, 102c, 102d connected to the intermediate circuit 100, there is an intermediate circuit filter 207a in the inverter 102a, which contains the intermediate circuit filter capacitor 205a and those on the positive conductor 103a or on the first conductor 103a connected positive intermediate circuit filter coil 203a and the negative intermediate circuit filter coil 204a connected to the negative conductor 104a or second conductor 104a.

Such an intermediate circuit filter 207a, 207b, 207c, 207d is located in every component 102a, 102b, 102c, 102d, which can serve as a potential interferer. However, it can also alternatively or additionally be arranged on the component connections of the intermediate circuit and thus be part of the intermediate circuit. Components 102a, 102b, 102c, 102d can share an intermediate circuit filter if they are close to each other are located in the same housing and are connected to the intermediate circuit 100 via a common supply line. The intermediate circuit capacitor 205a, 205b, 205c, 205d of an intermediate circuit filter is as close as possible to the active switching elements (in Fig. 2 not shown) of the respective component 102a, 102b, 102c, 102d. Thus, in each of these components 102a, 102b, 102c, 102d there is also an intermediate circuit capacitor 205b, 205c, 205d or intermediate circuit filter capacitor 205b, 205c, 205d with a capacity that is in the range from 10 to 1000µF. In addition, these components 102b, 102c, 102d are connected via filter inductors 203b, 204b, 203c, 204c, 203d, 204d, intermediate circuit filter inductors 203b, 204b, 203c, 204c, 203d, 204d or intermediate circuit inductors 203b, 204b, 203c, 204c, 203d, 204d with the DC link 100 connected. The battery 101 has an internal resistance 201 of 0.1Ω, which causes damping for the resonant circuit formed. The intermediate circuit 100 also has a line inductance 203 in the positive bus line 103 and a line inductance 204 in the negative bus line 104.

berechnet, wobei sich die Induktivität L aus der Zusammenschaltung der jeweiligen positiven und negativen Zwischenkreisfilterspulen 203a, 204a, 203b, 204b, 203c, 204c, 203c, 204c und die Kapazität C der jeweiligen Kapazität des zugehörigen Zwischenkreisfilterkondensators 205a, 205b, 205c, 205d entspricht.By interconnecting the respective filter capacitor 205b, 205c, 205 with the respective filter inductances 203b, 204b, 203c, 204c, 203d, 204d, the intermediate circuit filters 207a, 207b, 207c, 207d form a low-pass filter that filters out interference in the range of the typical clock frequency the respective component and the interference it generates and strongly attenuates interference with frequencies in this frequency range. Since the low-pass filter formed is a second-order filter, each filter has a resonance frequency. This resonance frequency f ₀ of each of the intermediate circuit filters 207a, 207b, 207c, 207d is determined according to the formula $f_{}$${}_0=\frac{1}{2\pi \sqrt{\mathit{LC}}}$

calculated, whereby the inductance L is calculated from the interconnection of the respective positive and negative intermediate circuit filter coils 203a, 204a, 203b, 204b, 203c, 204c, 203c, 204c and the capacitance C corresponds to the respective capacity of the associated intermediate circuit filter capacitor 205a, 205b, 205c, 205d.

This resonance frequency f ₀ is below the typical clock frequency of the component for which the intermediate circuit filter 207a, 207b, 207c, 207d is designed. The resonance frequency f ₀ is therefore in the pass band of the intermediate circuit filter. Consequently, the intermediate circuit filter 207a, 207b, 207c, 207d not only represents a damping device for the interference generated by the respective components, but also forms an oscillating circuit, which has the intermediate circuit filter capacitor 205a, 205b, 205c, 205d, the intermediate circuit filter coil and possibly also parts of the inductance of the supply line.

In the intermediate circuit 100 off Fig. 2 , in which no interference suppression device is used, the inductances of the supply lines with the respective intermediate circuit filter capacitor 205a, 205b, 205c, 205d contribute to the permeability for interference in the direction of the component 102a, 102b, 102c, 102d. However, the power inductor 203a, 204a, 203b, 204b, 203c, 204c, 203c, 204c is difficult to locate. This is in Fig. 2 shown as a coil component 203a, 204a, 203b, 204b, 203c, 204c, 203c, 204c. In order to be able to localize the line inductance in a practical exemplary implementation and to be able to arrange the interference suppression coil at this position, the supply line 103a, 104a, 103b, 104b, 103c, 104c, 103d, 104d can be replaced by a toroidal core and/or a plurality of toroidal cores (in Fig. 2 not shown). This toroidal core can also be used to increase the effectiveness of a coupling. If the supply line is led through the toroidal core, which is wound with the interference suppression coil, this line inductance acts as an intermediate circuit filter coil 203a, 204a, 203b, 204b, 203c, 204c, 203d, 204d, since the line inductance is increased by means of the toroidal cores. The intermediate circuit filter coil 203a, 204a, 203b, 204b, 203c, 204c, 203c, 204c guided through the toroidal core can also be referred to as coil L2. The interference suppression coil wound around the toroidal core can be referred to as L3.

To design suitable interference suppression devices for the intermediate circuit filters 207a, 207b, 207c, 207d, the components of the individual intermediate circuit filters 207a, 207b, 207c, 207d are taken into account. Although the intermediate circuit filters 207a, 207b, 207c, 207d are all excited together by the same interference source 206a, B1a, the exciting circuit 102a, which contains the interference source 206a, B1a, often has such a low impedance in comparison to the others when implemented Filter circuits 207b, 207c, 207d, so that the filter circuits 207b, 207c, 207d excited by the interference circuit 207a can be viewed as decoupled from one another in an approximation. Since all of the intermediate circuit filters 207a, 207b, 207c, 207d are connected via the intermediate circuit 100, their intermediate circuit filter capacitors 205a, 205b, 205c, 205d form with the intermediate circuit filter coils 203a, 204a, 203b, 204b, 203c, 204c, 203d, 204d and if necessary the line inductors 203a, 204a, 203b, 204b, 203c, 204c, 203d, 204d a network of resonant circuits 207a, 207b, 207c, 207d. In the exemplary embodiment according to Fig. 2 Only intermediate circuit filter capacitors 205a, 205b, 205c, 205d are shown. In this case they can Intermediate circuit filter capacitors 205a, 205b, 205c, 205d are also referred to as intermediate circuit capacitors. In another exemplary embodiment, intermediate circuit capacitors can be present in addition to the intermediate circuit filter capacitors (ZK filter capacitor). An intermediate circuit capacitor is defined as a capacitor that is connected directly to the switches, in particular to the semiconductor switches, of the components 102a, 102b, 102c, 102d, while a intermediate circuit filter capacitor 205a, 205b, 205c, 205d or intermediate circuit filter capacitor 205a, 205b , 205c, 205d is connected downstream of a filter choke 203a, 204a, 203b, 204b, 203c, 204c, 203d, 204d to form a filter circuit 207a, 207b, 207c, 207d. DC link filter capacitors and additional DC link capacitors are present, for example, in multi-stage filters.

Since different components are often interconnected via the intermediate circuit and the components work at different frequencies and, accordingly, the individual components contain filters with different resonance frequencies, it can happen that the working frequency of one component, for example the converter 102a, is exactly at the filter resonance frequency of another Component, for example the on-board power converter 102c, comes to rest and in particular comes to rest on the resonance frequency of the intermediate circuit filter 207c. Therefore, the resonant circuit formed by the elements 203c, 204c, 205c of the intermediate circuit filter 207c would be excited to oscillate. The working frequency corresponds to the typical clock frequency of the respective component. In the example described, the operating frequency of the converter 102a would essentially correspond to the resonance frequency f ₀ of the intermediate circuit filter 107c of the on-board power converter 102c. And even if the intermediate circuit filter tuned to the operating frequency of the interference component 102a suppresses the majority of the interference, interference of a corresponding frequency can spread on the intermediate circuit 100.

Exciting the filter resonance frequency in the intermediate circuit filter of the other component 102c can lead to such high losses in the chokes, coils and/or capacitors involved in the intermediate circuit filter of the other component 102c, for example in the components of the vehicle electrical system converter 102c, that the components (not in Fig. 2 shown) of the other component 102c can be overloaded and fail. In other words, exciting a resonant frequency in a DC link filter can result in a An increase in the amplitude of the vibration occurs, in particular an increase in voltage, which leads to an overload on individual components of the other component 102c, which can then fail as a result. This increase in tension is reflected in the figures Fig.4 , Fig. 5a and Fig.5b described. The components 102a, 102b, 102c, 102d are connected to the positive line 103 of the intermediate circuit 100 via the intermediate circuit filters 207a, 207b, 207c, 207d at the positive connection contacts V2a, V2b, V2c, V2d and via the negative connection contacts Na, Nb, Nc , Nd connected to the negative line 104 of the intermediate circuit 100.

Fig. 3 shows an equivalent circuit diagram for an interference suppression device 300, which is connected to an intermediate circuit and an intermediate circuit filter of a component, according to an exemplary embodiment of the present invention. The entire circuit 301 of Fig. 3 is a simulation diagram which essentially simulates the influence of the fault 206a on a faulty component 102c including the intermediate circuit filter 207c. Since the individual disturbances differ in the frequencies to which the respective intermediate circuit filter 207c reacts with resonance, it is permissible to consider each disturbance caused by a disturbance source B1a, 206a independently of the other disturbances. All elements that are subordinate to the simulation of the disturbance, such as the interconnection of the intermediate circuit 100 with the intermediate circuit filters 207b, 207c, 207d, which are not directly involved in the disturbance, are combined in the intermediate circuit 100 'and in particular in the lines 103'. The conductors 103c, 104c are connected to the associated conductors 103, 104 of the intermediate circuit 100.

The use of the interference suppression device 300 represents a measure which can be used to reduce the amplitude of a resulting interference oscillation V(VCc) or a resulting voltage amplitude V(VCc) at the intermediate frequency filter output VCc, which is caused by an input interference oscillation V _AC , V(V2c) is excited at a certain frequency at the intermediate circuit filter input V2c. The resulting interference oscillation V(VCc), which is generated at the intermediate frequency filter output VCc, may also be referred to as the resulting interference amplitude V(VCc) for simplicity. The component to be protected by the interference suppression device 300 or the interference filter 300 is in Fig. 3 not shown. However, this component could be the on-board power converter 102c, which was already mentioned in the description Fig. 2 was referred to as an example. The component to be protected 102c (not in Fig. 2 shown), for example the Vehicle electrical system converter 102c would be connected to the first conductor 103c at the connection VCc and to the second conductor 104c at the connection Mc. The interference suppression device 300 is dimensioned so that it can reduce the resulting amplitude of a voltage V(VCc), which is generated by a disturbance caused by an interference voltage from the intermediate circuit 100 'via the substantially resonant intermediate circuit filter 207c at the connection VCc is excited and thus keeps the voltage at the connection VCc, to which a component 102c to be protected can be connected, below a predeterminable maximum value. The interference suppression device limits a resulting voltage amplitude at a component connection VCc, Mc to a value that is harmless or acceptable for the component 102c and also keeps the associated power loss very small. This maximum value can, for example, be specified by an OEM for a specific frequency range.

überlagert ist, wobei f die Taktfrequenz der "Anregungsquelle" ist. Die größte "Anregungsquelle" ist meist der Umrichter 102a, von dem in Fig. 3 die von ihm verursachte Störung als Spannungsquelle B1, 206a modelliert ist.An intermediate circuit LC filter 207c, which has the intermediate circuit filter coil 203c, 204c, L2 and the intermediate circuit filter capacitor 205, C, is connected to an intermediate circuit 100' at a connection V2c, Nc. The intermediate circuit 100' is supplied with a direct voltage of 900V by the supply battery 101 or direct current source 101 with the intermediate circuit direct voltage VB=Vbatt-Ri*I, minus the voltage at Ri, which is caused by a current I flowing through Ri. The battery 101 has a voltage source 101 'with a constant voltage Vbatt of 900V and the internal resistance Ri, 201, which can be, for example, 100mΩ. Periodic or alternating interference voltages V _AC can be superimposed on this direct voltage VB. These interference voltages can be caused by switched components that can excite periodic interference signals during their switching processes. The switched components do have filters that are intended to suppress the periodically excited interference. However, it may happen that the filters cannot completely eliminate all interference. The strongest disturbances may be caused by the components that switch the greatest power in an intermediate circuit 100'. A disturbance, an interference signal or an interference voltage may be superimposed on the existing DC voltage VB. The voltage that thus occurs on the intermediate circuit 100 'is a direct voltage VB = 900V, which has a periodic interference voltage of, for example $v_{\mathit{AC}}=20v\ast 〚\sin (\square 〛2\mathit{\pi ft})$

is superimposed, where f is the clock frequency of the “excitation source”. The biggest “source of stimulation” is usually the Inverter 102a, from which in Fig. 3 the disturbance caused by it is modeled as a voltage source B1, 206a.

For the simplified scheme in Fig.3 It is now assumed that the two supply lines 103a, 104a, 103b, 104b, 103c, 104c, 103d, 104d of all components lead to the battery 101 in a "star shape" and are all connected there at one connection point. The lead inductances 203, 204 are in Fig.3 not shown.

The coil L0 is the combination of the inductors 203a, 204a including leads 103a, 104a to the converter 102a, and L1 is the summary of the inductors 203c, 204c and leads 103c, 104c to the intermediate circuit filter 207c.

The interference suppression device 300 for the direct current circuit 100' or intermediate circuit 100', which has two conductors 103c, 104c, comprises a first connection VCc, for connecting the interference suppression device to the first conductor 103' of the direct current circuit 100', in particular to a first conductor 103c of the intermediate circuit filter 207c of the component 102c to be protected. Furthermore, the interference suppression device 300 comprises a second connection Mc, for connecting the interference suppression device 300 to a second conductor 104 'of the direct current circuit 100', in particular to a second conductor 104c of the intermediate circuit filter 207c of the component 102c to be protected. The interference filter 300 or the interference suppression device 300 is connected in parallel to the intermediate circuit filter capacitor 205c and in series to the intermediate circuit filter coil L2, 203c, 204c. This intermediate circuit filter coil L2, 203c, 204c is designed as a discrete component in the intermediate circuit filter 207c, so that this coil L2, 203c, 204c can be localized very precisely in the intermediate circuit filter.

The connections VCc, Mc of the interference filter can have connecting cables. Connected to the connections VCc, Mc, the interference suppression device 300 has a sensor 300 ', which is set up to reduce interference that endangers the elements of the component 102c. The component 102c is also connected in parallel to the interference suppression device 300 at the connections VCc, Mc. To counteract or compensate for this, the sensor 300' is set up to detect when a predeterminable limit value of a superimposed alternating voltage V _AC is exceeded in the first conductor 103', 103c of the direct current circuit 100' and in particular in the intermediate circuit filter 207c. The sensor 300' is also contactless or galvanically isolated from the direct current circuit 100' or Intermediate circuit 100 'and in particular with the intermediate circuit filter 207c of the intermediate circuit 100' can be coupled. By applying a supply line 103c, 104c to a toroidal core, the coil L2 of the intermediate circuit filter is formed in order to enable effective coupling to the sensor 300'. The sensor 300' is set up to essentially reduce the resulting alternating interference voltage in the first conductor of the direct current circuit to the predeterminable limit value by impressing a current into the first connection VCc. In other words, the resulting voltage V(VCc) between the connections VCc and Mc is regulated below a maximum value by generating a current that can be impressed into the first sensor connection VCc in the event of an increase in the amplitude of the voltage V(VCc). To counteract an increase in amplitude.

The sensor 300' has one or more additional windings L3, chokes L3 or coils L3, which are magnetically coupled to the filter choke L2, 203c, 204c of the intermediate circuit filter 207c, for example by winding on a common ferrite core or toroidal core. The coils L2, 203c, 204c and L3 then form a transformer. If there is no filter choke L2 in the intermediate circuit 100' or in the intermediate circuit filter 207c, it can be subsequently installed in the supply line 103', 104', 103c, 104c, for example by routing at least one of the supply lines 103c, 104c through a toroidal core.

In addition to the magnetic or non-contact coupling of the coils L2, 203c, 204c, a connection of the filter coil L2, 203c, 204c in the connection VCc is coupled to a connection of the sensor coil L3. In the connection VCc, the connections of the filter coil L2 and the sensor coil L3 are also connected to a connection of the filter capacitor C, 205c. The other terminal of the filter capacitor C, 205c is connected to the second sensor terminal Mc. At the second connection of the sensor coil L3, 302, at least one connection of a sensor capacitor C3, 303 is connected in series with the sensor coil L3, 302. The sensor coil L3, 302 and the sensor capacitor C3, 303 thus form a series resonant circuit. A second terminal of the sensor capacitor C3, 302 is connected to the anode of a feedback diode D1, 304. The cathode of the feedback diode D1, 304 is connected to the connection VCc. A current picked up and amplified by the sensor coil L3, 302 from the intermediate circuit 100' and in particular from the intermediate circuit filter 207c can be impressed into the connection VCc via the feedback diode D1, 304. The anode of the feedback diode D1, 304 is also one with the cathode Connection diode D2, 305 connected. The anode of the connection diode is connected to the second connection Mc. Consequently, the first terminal VCc and the second terminal Mc are connected to each other via the feedback diode D1, 304 and the connection diode D2, 305. In an installed state in which the interference suppression device 300 is connected in parallel to the intermediate circuit filter capacitor C, 305, the connection diode D2, 305 is essentially connected in parallel to the intermediate circuit filter capacitor C, 305. The second connection is connected to the connection Nc and to reference potential or ground if the interference suppression device is connected to the intermediate circuit filter.

The sensor capacitor C3, 303 can also be realized from a large number of capacitors C3, C4 connected essentially in parallel. The diodes D1, 304, D2, 305 can be implemented as a single diode or as a plurality of diodes D1, D2, D3, D4.

In the in Fig. 3 In the example shown, the windings of the coils L2, 203c, 204c and L3, 302 form a transformer with a specific coupling factor k, for example k=0.9. An external periodic disturbance V _AC , which is caused by the disturbance source B1a, 206a, causes a resonant overvoltage across L2 and, because of the coupling, therefore also across L3. If the interference voltage caused is sufficiently large and the voltage ratio, which results from the ratio of the number of windings of the coupled coils L3, 302, L2, 203c, 204c of the transformer they form, is also large enough, a periodic current begins across the sensor capacitor C3, 303 and the sensor diodes 304, D1, 305, D2 to flow. This current induced in the sensor 300', which is proportional to the superimposed disturbance V _AC in the direct current circuit 100' and in particular to the disturbance V _AC in the intermediate circuit filter 207c, is impressed into the connection VCc and limits the resonant overvoltage resulting from the resonance V _AC in that the energy generated by the transformer coupling in the sensor is diverted into the intermediate circuit 100 'and in particular into the intermediate circuit filter 207c through the impressed current.

auf. Hierbei schwingt die Störung V_AC um den Arbeitspunkt 900V. Diese Störung wirkt in einer Richtung vom Zwischenkreis 100' in Richtung Komponente 102c, die an den Anschlüssen VCc und Mc angeschlossen ist, auf das Zwischenkreisfilter 207c, obwohl dieses Filter 207c ursprünglich zur Dämpfung von Störungen vorgesehen ist, die sich von der Komponente 102c auf den Zwischenkreis 100' ausbreiten. Im Bereich der Resonanzfrequenz reagiert die resultierende Spannung an dem Anschlusspaar VCc, Mc mit einer Erhöhung der Amplitude, die zu einem erhöhten Strom in der Zwischenkreisfilterspule L2, 203c, 204c führt. Der Transformator überträgt lediglich den periodischen Anteil der überhöhten Spannung, die an VCc anliegt. Das Windungsverhältnis beträgt beispielsweise 1:20. Folglich wird die überhöhte Spannung mit einer entsprechenden Spannungsübersetzung in den Sensor 300' übertragen. Da die Spulen L2, 203c, 204c und L3, 302 jedoch den gemeinsamen Anschluss VCc haben, pendelt die in dem Sensor induzierte Spannung nicht um den Arbeitspunkt des Zwischenkreis 100, 100' von 900V sondern lediglich um das Mittenpotential zwischen 0 und +900V, also 450V. Solange die induzierte Spannung diese 450V nicht überschreitet, werden die Dioden 304,305 nicht leitend. Wird die induzierte Spannung über L3 grösser als 450V - d.h., die Spannung über L2 ist grösser als 450V/20 = 22.5V -, dann beginnen die Dioden 304, 305 zu leiten und führen einen Teil der in der Schwingung gespeicherten Energie in den Zwischenkreis 100' ab. Das Windungsverhältnis wird so gewählt, dass auch bei der kleinsten auftretenden Zwischenkreisspannung nur das Überschwingen durch die Dioden begrenzt wird. Beim Auftreten der größten spezifizierten Störspannung V_AC = V_ripple soll die Begrenzung nicht wirksam werden, wenn der Filter-Schwingkreis 207c nicht angeregt wird.In other words, for example, the voltage V(V2c), which comes from the intermediate circuit through a superposition of the periodic interference V _AC from the interference source B1a, 206a and the DC voltage VB, has the curve $v\left(v2c\right)=\mathit{VB}+v_{\mathit{AC}}=900v+20v\ast 〚\sin (\square 〛2\mathit{\pi ft})$

on. Here the disturbance V _AC oscillates around the operating point 900V. This disorder acts in a direction from the intermediate circuit 100' towards component 102c, which is connected to the connections VCc and Mc, to the intermediate circuit filter 207c, although this filter 207c is originally intended to attenuate interference that propagates from the component 102c to the intermediate circuit 100' . In the range of the resonance frequency, the resulting voltage at the connection pair VCc, Mc reacts with an increase in amplitude, which leads to an increased current in the intermediate circuit filter coil L2, 203c, 204c. The transformer only transfers the periodic portion of the excess voltage present at VCc. The turns ratio is, for example, 1:20. Consequently, the excess voltage is transmitted to the sensor 300' with a corresponding voltage ratio. However, since the coils L2, 203c, 204c and L3, 302 have the common connection VCc, the voltage induced in the sensor does not fluctuate around the operating point of the intermediate circuit 100, 100' of 900V but only around the center potential between 0 and +900V, i.e 450V. As long as the induced voltage does not exceed 450V, the diodes 304,305 do not conduct. If the induced voltage across L3 is greater than 450V - that is, the voltage across L2 is greater than 450V/20 = 22.5V - then the diodes 304, 305 begin to conduct and lead part of the energy stored in the oscillation into the intermediate circuit 100 ' away. The turns ratio is chosen so that even with the smallest intermediate circuit voltage that occurs, only the overshoot is limited by the diodes. When the largest specified interference voltage V _AC = V _ripple occurs, the limitation should not take effect if the filter resonant circuit 207c is not excited.

A closer look reveals the following exemplary usable dimensions. In the example, V _ripple = 16Vpk (peak voltage) and V _DCmin = 450VDC (voltage of the direct current component) as well as a number of turns n ₃ of the coil L3 and n ₂ of the coil L2 are assumed: $$\frac{n_3}{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">n</figure-callout>}}_2}=\sqrt{\frac{L_3}{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}}\approx \frac{{\mathrm{<figure-callout\; id="2"\; label="v\; DC\; min"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\mathit{DC}\min }}{\sqrt{2}\cdot v_{\mathit{ripple}}}=\frac{450\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">v</figure-callout>}}{\sqrt{2}\cdot 16v_{\mathit{pk}}}\approx 20$$

This results in a turns ratio of 1:20. L2 and C are already predetermined by the dimensioning of the component and the associated intermediate circuit filter 207c. A coupling k=0.9 may lead to a good result, and C3 is chosen so that the smallest possible inductor current through L2, 203c, 204c results across all operating points. A good result can be achieved, for example, if C3 is chosen so that: $$C_3\cdot L_3\approx 1.6\cdot C\cdot L_2\mathrm{d}\mathrm{.H}\mathrm{.}{C}_3\approx C\cdot 1.6\cdot {\left(\frac{n_2}{n_3}\right)}^2$$

Table 1 shows the dimensioning of the components of the circuit Fig. 3 at. Herein C3 is determined according to the dimensioning rule given above. Table 1 Ri 100mΩ L0 2.5µH Vbatt 900V L1 2.5µH C 20µF L2 26.35µH C3 80nF L3 10.54mH

Fig. 4 shows a selection of four frequency diagrams 400 for an interference signal with a low interference amplitude according to an exemplary embodiment of the present invention. The circuit was designed for the simulation Fig. 3 , which represents an equivalent circuit diagram for a real intermediate circuit in an electric vehicle, is subjected to a constant interference amplitude of 2V and a variable frequency. In the diagram 400, the frequency from 0ms to 200ms or 0 to 20kHz is plotted on the abscissa 401. The abscissa can be calibrated in milliseconds (ms), whereby the values can be converted into the associated frequency using the conversion factor 1kHz/10ms, so that a frequency range from 0 Hz to 20kHz is shown on the abscissa. The voltage coordinate 402 indicates voltage values in the range from 855V to 945V. The current coordinate 403 indicates current values from -30A to +30A.

angelegt. Der Verlauf der Störspannung V(V2c), 410 ist in Fig. 4 eingezeichnet. Die Störamplitude der Störspannung beträgt V_AC = 2V insbesondere V_ripple = 2Vpk. Der Spannungsverlauf V(VCc), 411 am Filterausgang an den Komponentenanschlüssen VCc, Mc über dem Zwischenkreiskondensator C, 205c zeigt, dass sich, obwohl sich im Bereich von 6,5 kHz eine Resonanz und insbesondere auch eine Strom- und Spannungsüberhöhung ausbildet, wegen der kleinen Anregung mit einer Störamplitude von 2V nur eine unschädliche Spannungsamplitude von 35V bleibt. Die Entstörvorrichtung kommt daher nicht zum Einsatz, da eine maximal zulässige Spannung an den Anschlüssen VCc, Mc nicht überschritten wird.In order to be able to display the effects with variable frequency, the sweep function is used at connection V2c $v\left(v2c\right){=}_{\square }900v+2v\ast 〚\sin (\square 〛2\pi \ast 50000\frac{1}{s^2}{t}^2)$

created. The course of the interference voltage V(V2c), 410 is in Fig. 4 drawn. The interference amplitude of the interference voltage is V _AC = 2V, in particular V _ripple = 2Vpk. The voltage curve V(VCc), 411 at the filter output at the component connections VCc, Mc across the intermediate circuit capacitor C, 205c shows that, although a resonance and in particular an increase in current and voltage develops in the range of 6.5 kHz, due to the Small excitation with an interference amplitude of 2V is only harmless Voltage amplitude of 35V remains. The interference suppression device is therefore not used because a maximum permissible voltage at the connections VCc, Mc is not exceeded.

Likewise, the current I(L2), 412 through L2 remains below 24A. The current through L3 I(L3), 413 remains essentially constant, as shown by curve 413, which is valued by a factor of 10.

angelegt, also verglichen mit der Störspannung aus Fig. 4 mit einer zehnfachen Störamplitude. Der Verlauf der Störspannung V(V2c), 410' ist in Fig. 5a eingezeichnet. Der Spannungsverlauf V(VCc), 411' am Filterausgang an den Komponentenanschlüssen VCc, Mc über dem Zwischenkreiskondensator C, 205c zeigt, dass sich, obwohl sich in einem breiten Frequenzbereich um wiederum 6,5 kHz eine Resonanz und insbesondere auch eine Strom- und Spannungsüberhöhung ausbildet, die wegen dem Eingreifen der Entstörvorrichtung 300 auf eine Spannungsamplitude von 45V, d.h. von 855V bis 945V begrenzt wird. Gegenüber Fig.4 wird durch die Wirkung der Entstörvorrichtung der Schwerpunkt der Resonanz zu einer etwas tieferen Frequenz verschoben. Wie bereits angeführt, lässt sich mit der oben angegebenen Dimensionierung für C3 ein gutes Ergebnis erreichen. Somit kann sichergestellt werden, dass eine an VCc angeschlossene Komponente nicht mit einer Spannungsamplitude von mehr als 45V belastet wird, wenn beispielsweise gefordert wird, dass über den Frequenzbereich von 0Hz bis 20kHz keine größeren Belastungen auftreten sollen oder, dass größere Belastungen vermieden werden. Fig. 5a shows a selection of frequency diagrams 400' for an interference signal with a large interference amplitude at 900VDC intermediate circuit voltage according to an exemplary embodiment of the present invention. The sweep function is used at connection V2c $v\left(v2c\right){=}_{\square }900v+20v\ast 〚\sin (\square 〛2\pi \ast 50000\frac{1}{s^2}{t}^2)$

applied, i.e. compared to the interference voltage Fig. 4 with a tenfold interference amplitude. The course of the interference voltage V(V2c), 410' is in Fig. 5a drawn. The voltage curve V(VCc), 411' at the filter output at the component connections VCc, Mc across the intermediate circuit capacitor C, 205c shows that, although there is a resonance and in particular an increase in current and voltage in a wide frequency range around 6.5 kHz which is limited to a voltage amplitude of 45V, ie from 855V to 945V, due to the intervention of the interference suppression device 300. Opposite Fig.4 The center of gravity of the resonance is shifted to a slightly lower frequency due to the effect of the interference suppression device. As already stated, a good result can be achieved with the dimensioning for C3 given above. This makes it possible to ensure that a component connected to VCc is not loaded with a voltage amplitude of more than 45V if, for example, it is required that no larger loads should occur over the frequency range from 0Hz to 20kHz or that larger loads should be avoided.

ergäbe sich ohne das Vorhandensein der Entstörvorrichtung 300 auch die 10-fache Spannung, denn das System ohne Entstörvorrichtung verhält sich linear aufgrund der Tatsache, dass es nur lineare Bauteile aufweist.The current I(L2), 412` through coil L2 remains below 30A over the entire frequency range. The course of the current curve I(L3), 413` shows that in a range from 5.2kHz to 8.6kHz a high current flows through L3 and therefore the interference suppression device becomes active. Without the intervention of the interference suppression device, the voltage amplitude V(VCc), 411' would reach a voltage amplitude of 350V in the frequency range around 6.5 kHz, which could destroy a component connected to VCc. In the example below Fig. 4 The interference suppression device does not intervene due to the low excitation voltage. Due to the 10-fold stimulation compared to that of the Fig.4 underlying excitation function $v\left(v2c\right){=}_{\square }900v+2v\ast 〚\sin (\square 〛2\pi \ast 50000\frac{1}{s^2}{t}^2)$

Without the presence of the interference suppression device 300, the voltage would be 10 times higher, because the system without the interference suppression device behaves linearly due to the fact that it only has linear components.

angelegt, also verglichen mit der Störspannung aus Fig. 4 mit einer zehnfachen Störamplitude von 20V, jedoch bei einem geringeren Arbeitspunkt von 450VDC. Der Verlauf der Störspannung V(V2c), 410" ist in Fig. 5b eingezeichnet. Der Spannungsverlauf V(VCc), 411" am Filterausgang an den Komponentenanschlüssen VCc, Mc über dem Zwischenkreiskondensator C, 205c zeigt, dass sich, obwohl sich in einem breiten Frequenzbereich um wiederum 6,5 kHz eine Resonanz und insbesondere auch eine Strom- und Spannungsüberhöhung ausbildet, diese wegen dem Eingreifen der Entstörvorrichtung 300 auf eine Spannungsamplitude von 30V, d.h. von 420V bis 480V begrenzt wird. Gegenüber Fig.4 wird durch die Wirkung der Entstörvorrichtung der Schwerpunkt der Resonanz zu einer etwas tieferen Frequenz verschoben. Wie bereits angeführt, lässt sich mit der Dimensionierung $C_3\approx C\cdot \mathrm{1,6}\cdot {\left(\frac{n_2}{n_3}\right)}^2$

ein gutes Ergebnis erreichen. Somit kann sichergestellt werden, dass eine an VCc angeschlossene Komponente nicht mit einer Spannungsamplitude von mehr als 36V belastet wird, wenn beispielsweise gefordert ist, dass über den Frequenzbereich von 0Hz bis 20kHz keine größeren Belastungen auftreten sollen oder über diesen Bereich größere Belastungen vermieden werden sollen. Fig. 5b shows a selection of frequency diagrams 400" for an interference signal with a large interference amplitude at 450V intermediate circuit voltage according to an exemplary embodiment of the present invention. The voltage ordinate 402" indicates voltage values in the range from 405V to 495V. The current coordinate 403" indicates current values from -35A to +35A. The sweep function is used at connection V2c $v\left(v2c\right){=}_{\square }450v+20v\ast 〚\sin (\square 〛2\pi \ast 50000\frac{1}{s^2}{t}^2)$

applied, i.e. compared to the interference voltage Fig. 4 with a tenfold interference amplitude of 20V, but at a lower operating point of 450VDC. The course of the interference voltage V(V2c), 410" is in Fig. 5b drawn. The voltage curve V(VCc), 411" at the filter output at the component connections VCc, Mc across the intermediate circuit capacitor C, 205c shows that, although there is a resonance and in particular an increase in current and voltage in a wide frequency range around 6.5 kHz forms, this is limited to a voltage amplitude of 30V, ie from 420V to 480V, due to the intervention of the interference suppression device 300. Opposite Fig.4 The center of gravity of the resonance is shifted to a slightly lower frequency due to the effect of the interference suppression device. As already mentioned, the dimensioning can be done $C_3\approx C\cdot 1.6\cdot {\left(\frac{n_2}{n_3}\right)}^2$

achieve a good result. This makes it possible to ensure that a component connected to VCc is not loaded with a voltage amplitude of more than 36V if, for example, it is required that no major loads should occur over the frequency range from 0Hz to 20kHz or that greater loads should be avoided over this range.

ergäbe sich ohne dem Vorhandensein der Entstörvorrichtung 300 auch die 10-fache Spannung, denn das System ohne Entstörvorrichtung verhält sich linear, da es nur lineare Bauteile aufweist.The current I(L2), 412" through the coil L2 remains below 35A over the entire frequency range and is slightly larger in a narrow frequency range than a corresponding value of curve 412' in Fig. 5a . The course of the current curve I(L3), 413" shows that in a range from 4.5 kHz to 11 kHz a high current flows through L3 and therefore the Suppression device becomes active. Without the intervention of the interference suppression device, the voltage amplitude V(VCc), 411" in the frequency range around 6.5 kHz would reach a voltage amplitude of 350V, which could destroy a component connected to VCc. In the example Fig. 4 The interference suppression device does not intervene due to the low excitation voltage. Due to the 10-fold stimulation compared to that of the Fig.4 underlying excitation function $v\left(v2c\right){=}_{\square }900v+2v\ast 〚\sin (\square 〛2\pi \ast 50000\frac{1}{s^2}{t}^2)$

Without the presence of the interference suppression device 300, the voltage would be 10 times higher, because the system without the interference suppression device behaves linearly since it only has linear components.

Fig. 6 shows a further embodiment of an interference suppression device 300a according to an exemplary embodiment of the present invention. This configuration allows the use of more cost-effective components for the sensor 300'a. The turns ratio is 1:10 which allows the use of a coil L3 with a lower inductance that can be manufactured more cheaply. However, the coupling factor is as in Fig. 3 k = 0.9. The capacitor C3, 303 is replaced by a pair of capacitors 303', C3', C4 and instead of the diodes D1, D2, four diodes D1', D2', D3, D4 are used, which are arranged in a series connection. A resistor R1, R2, R3, R4 is connected in parallel with each of the diodes.

The intermediate circuit filter 207c` also has a different structure than the intermediate circuit filter 207c Fig. 3 . Instead of the capacitance C, a series connection of the capacitors C1, C2 is used in order to be able to connect the anode of the diode D2` and the cathode of the diode D3 between the connection of the capacitors C1, C2.

Resistors R1, R2, R3, R4 are optional but can be used to ensure convergence in a simulation. Although the structure of the interference suppression device 300a is in Fig. 6 from the structure of the interference suppression device 300 Fig. 3 differs, the basic functionality of the interference suppression devices 300, 300a is essentially the same. However, in the interference suppression device 300a, due to the series connection of two diode half-bridges D1', D2' and D3, D4, only half the voltage at L3' compared to the voltage at L3, 302 is required for the circuit 300a to intervene. Accordingly, the number of turns of L3 'of the interference suppression device 300a can be halved compared to the number of turns of L3, 302, of the interference suppression device 300. With a coupling k=0.9, good results can be achieved, and the capacitances of the capacitors C3` and C4 are chosen so that C3`=C4 and that the smallest possible inductor current through L2 results across all operating points. The capacitors C3' and C4 are connected to a common terminal both to each other and to a terminal of the coil L3'. The other terminal of the capacitor C3' is connected to an anode of the diode D1' and a cathode of the diode D2'. The diodes D1' and D2' form a diode half bridge. The other terminal of the capacitor C4 is connected to an anode of the diode D3 and a cathode of the diode D4. The diodes D3 and D4 form another diode half bridge. A good result can be achieved if C3`=C4 is chosen, where the values of C3' and C4 are chosen such that when C1=C2 the following condition is fulfilled: $$C_3\prime \approx C_1\cdot 1.8\cdot {\left(\frac{n_2}{n_3}\right)}^2$$

Table 2 shows the dimensioning of the components of the circuit Fig. 6 at. From this dimensioning according to Table 2 it can be seen that the conditions C1=C2 and C3`=C4 are met. In addition, the values of the capacitors C3' and C1 are in the relationship stated above. Table 2 Ri 100mΩ L0 2.5µH Vbatt 900V L1 2.5µH C1 40µF L2 26.35µH C2 40µF L3' 2.635mH C3' 180nF R1=R2=R3=R4 1MΩ C4 180nF

In addition, it should be noted that “comprising” and “having” do not exclude other elements or steps and “a” or “an” does not exclude a plurality.

Reference symbols in the claims are not to be viewed as a limitation.

Claims (8)

1. Circuit for distortion cancellation (300, 300a) in a DC circuit (100, 100'), which has two conductors (103', 103c, 104', 104c),

   wherein the circuit for distortion cancellation (300, 300a) comprises:

   - a first component connection (VCc) for connecting the circuit for distortion cancellation (300, 300a) to a first conductor (103', 103c) of the DC circuit (100, 100');

   - a second component connection (Mc) for connecting the circuit for distortion cancellation (300, 300a) to a second conductor (104', 104c) of the DC circuit (100, 100');

   - a sensor (300', 300a'), wherein the sensor:

   - is transformer-coupled to a DC circuit (100, 100');

   - is equipped to detect an exceeding of a predetermined limit of a superimposed AC current in the first conductor (103', 103c) of the DC circuit; and

   - is equipped to reduce the AC current in the first conductor of the DC circuit to the predetermined limit by applying a current into the first component connection (VCc);

   wherein the sensor (300', 300a') has a coil (302, L3; L3') for transformer-coupling to the first conductor of the DC circuit in order to form a transformer with the DC circuit (100, 100') having a predetermined coupling factor (k);

   wherein a first connection of the coil (L3; L3') is connected to the first component connection (VCc), characterized in that

   a second connection of the coil (L3; L3') is connected to the first component connection (VCc) via at least one capacitor (303, C3; C3', C4) and via at least one diode (D₁, 304, D₂, 305; D1', D2', D3, D4);

   wherein a connection of the at least one capacitor (C3; C3', C4) is connected to the second component connection (Mc) via a further diode (D2; D4);

   wherein the anode of the at least one diode (D₁, 304, D₂, 305; D1', D2', D3, D4) is connected to the cathode of the further diode (D2; D4).
2. Circuit for distortion cancellation (300, 300a) according to claim 1,
   wherein the first component connection (VCc) and the second component connection (Mc) is designed for connecting to a vehicle component (102a, 102b, 102c, 102d) .
3. Circuit for distortion cancellation (300, 300a) according to claim 1 or 2,
   whose sensor (300', 300a') is equipped to be coupled to a filter coil (L2, 203c, 204c) and/or to a lead inductance (L2, 203c, 204c) of the DC circuit.
4. Circuit for distortion cancellation (300, 300a) according to one of claims 1 to 3,
   which is equipped to be coupled to a DC circuit (100, 100') which has a DC voltage of 400 V or 900 V.
5. Circuit for distortion cancellation (300, 300a) according to one of claims 1 to 4,
   further having: a housing; wherein the housing is designed for fastening to a vehicle.
6. Component (102a, 102b, 102c, 102d) having:

   - a DC circuit (100, 100') with a first conductor (103', 103c), a second conductor (104', 104c), and a DC link filter (207c, 207c') in the first conductor;

   - a circuit for distortion cancellation (300, 300a) according to one of claims 1-5; wherein

   - the first component connection (VCc) of the circuit for distortion cancellation is connected to the first conductor (103', 103c);

   - the second component connection (Mc) of the circuit for distortion cancellation is connected to the second conductor (104', 104c);

   - the sensor (300', 300a') is transformer-coupled to the DC link filter (207c, 207c'); and

   - the DC circuit is equipped for connecting to a high-voltage DC link.
7. High-voltage DC link (100, 100') for a vehicle having:

   - a supply battery (101);

   - a first component (102a) which is operated at an operating frequency;

   - at least one second component (102b, 102c, 102d);

   - at least one circuit for distortion cancellation according to one of claims 1-5;
   wherein

   - the supply battery, the first component, and the second component are each connected to a first conductor and to a second conductor of the high-voltage DC link;

   - the first conductor of the at least one second component is connected to the first component connection (VCc) of the circuit for distortion cancellation;

   - the second conductor of the at least one second component is connected to the second component connection (Mc) of the circuit for distortion cancellation; and

   - the sensor (300', 300a') of the circuit for distortion cancellation is transformer-coupled to the part of the first conductor associated with at least the second component.
8. Vehicle having at least one subject matter selected from:

   - the circuit for distortion cancellation according to one of claims 1-5;

   - the component according to claim 6;

   - the high-voltage DC link according to claim 7.

Images